The present invention relates to a method to handle with polyphony limits in an electronic organ.
An electronic organ typically comprises: two keyboards (a higher and a lower keyboard), one pedalboard, a series of organ stops, which can be turned on by a user to determine which voices are assigned to each key and to each pedal, and with a sound module, which is provided with a number of independent sound generators.
Under normal operating conditions, when a user presses a key/pedal, the sound module activates some sound generators that generate all the active voices associated with a key/pedal independently. However the number of independent sound generators inside the sound module is limited and under particular conditions it can prove to be insufficient to simultaneously generate all the voices required by the user""s commands; such kind of situation is usually referred to as xe2x80x9cpolyphony shortagexe2x80x9d, it results from the limited voice polyphony of the instrument and it may happen rather often: for example, a good electronic organ is usually provided with 128 independent sound generators, but the simultaneous generation of 252 independent voices is required in extreme operating condition, that is when all the 26 stops of the electronic organ are turned on, all couplers are turned on and the organist presses 10 keys and 2 pedals simultaneously.
In the state-of-the-art electronic organs, when a polyphony shortage occurs, polyphony limits are managed dynamically since instantaneously less significant voices are sorted out and suppressed, this meaning that in that precise moment some voices are evaluated by the sound module and judged as negligible in terms of a correct music perception by listeners. The dynamic suppression of instantaneously less significant voices is an effective method to cope with polyphony limits; however, the dynamic suppression of voices causes a decrease in the overall sound quality level because it brings about some slight though continual change in the sound composition. Moreover, a dynamic suppression of voices forces the sound module to sort out and eliminate a sometimes high number of voices in realtime, with a consequent remarkable utilization of calculation power; of course to assure the necessary calculation power under every circumstance, the sound module has to be provided with a powerful and therefore costly processor.
The purpose of this invention is to supply a method to handle with polyphony limits in an electronic organ, which is deprived of the above mentioned disadvantage while granting an easy and cost-effective implementation at the same time.
According to the present invention, a method is provided to handle with polyphony shortage in an electronic organ comprising at least one keyboard, one pedalboard, a series of organ stops that can be turned on by the user to associate certain voices to every key and every pedal, and a sound module, that is provided with a number of independent sound generators; the method comprising the step of:
determining a maximum number of organ stops, which can be turned on simultaneously, said maximum number depending on the number of the provided independent sound generators;
determining a selection rule for turning off said organ stops; and
automatically turning off some organ stops according to said selection rule whenever a user turns on a number of stops exceeding said maximum number, so as to obtain a number of actually operating stops which does not exceed said maximum number.